Dynamic speakers are the most widely used speakers in the world. As an electroacoustic transducer, the dynamic speaker produces mechanical energy and a large amount of excess thermal energy while generating acoustic energy. This energy conversion is one-way irreversible.
Among them, 90% of the input electric energy is converted into the Joule heat energy of the voice coil. This heat causes the temperature of the voice coil to rise sharply while heating the entire magnetic circuit system of the speaker (including the washer, magnet and T-iron). If the heat generated by the speaker is not dissipated in time, it will easily cause the neodymium magnet to demagnetize at a high temperature, and the voice coil may be burned at a high temperature, which severely limits the resistance power of the speaker. Sometimes, in order to increase the resistance power of the speaker, it is forced to use a voice coil and a neodymium magnet with a higher temperature resistance level, but this not only causes a sharp rise in the cost of the speaker, but the power boost in this manner is rather limited.
At present, the methods commonly used in the industry to improve the heat dissipation of speakers mainly include (1) using metal skeletons and drum papers; (2) increasing forced convection and opening holes in the parts to allow more air to flow through the surface of the voice coil to remove heat; and (3) blackening the magnetic circuit and voice coil to increase radiation efficiency.
However, among the above three methods, (1) when using a metal skeleton and a drum paper, since the internal damping is small, the sound quality is hard, which has a large influence on the sound output; (2) the efficiency of heat dissipation by forcing convection to the voice coil is limited, especially when the heat source is hidden in the speaker, the convection effect is poor; and (3) although blackening the magnetic circuit and the voice coil is beneficial to the heat radiation between the two, the magnetic circuit will rise to a certain temperature quickly, and finally reach the heat balance, then the heat dissipation may not be continued.
Therefore, it is necessary to optimize the design of the existing speaker system, so that while reducing the overall temperature of the speaker, it is desirable to utilize the excess heat energy generated by the speaker.